Hi guys,
as you may have read in other threads of this forum, I'm racing a Europa S2 with 807 Renault engine. After several very disappointing years (2021 - 2023), I chose to do some major (at least in relation to my budget) investments into the performance and relaibility of the car. A whole new engine from a Renault Alpine expert and a new shorter differential are the two most significant upgrades, which occupied a huge chunk of my racing budgets from 2023 and 2024. But still, there is that 25 years old exhaust in my car, which was selfmade by a previous owner. I want to get rid of it ASAP, because it's ugly and heavy. If the replacement exhaust delivers a couple more horsepower, that would be a bonus on top. The only problem is the budget. I have no budget left for a custom-built exhaust. That's why I'm trying to find a way, which means a lot bang for buck: The x-flow header from Lotus Supplies aka. Banks Engineering (
https://www.lotus-supplies.com/parts/exhaust/renault/exhaust-header-hand-formed-renault-x-flow-s2/).
I would like to share some thoughts about that Banks exhaust manifold: I purchased it, because it's cheap and looks like a good design for gas flow, especially in relation to the costs. But as my racing racing engine with 1597 cc has big valves and revs up to 7300 RPM, my feeling is that the step from four Ø42 mm tubes into one Ø48 mm tube is too small. From research in books and magazines, I found that such a step would even be considered small in a 2-1 collector, not to mention 4-1.
In addition, my exhaust ports are diamond-shaped and that form does not match the exhaust flange. I tried to grind them bigger, but there is not enough material on the original flange. Thus, I have to change the flange in order to use the Banks manifold. And while I'm already at it, I will also increase the diameter of the collector tube to 52 mm, so that I can fit a 55 mm muffler to it.
My new enigne didn't do a maximum power run on the dyno so far, but I would like to do one soon. The only dyno-run so far was right after the engine was built, two hours after start-up during the break-in phase. There it was shortly reved up to 6000 RPM and delivered 140 HP and 163 Nm. My target is something around 160 HP at ~7000 RPM and from the diagram, this should be possible.
Valerio Leone (former member of this community) used the Banks manifold in his race car, but he sold the car and deleted his socials lately. Funnily, I'm going to meet the new owner of his car today. It was sold from Italy to Germany, very near to my place. I'm going to have a chat with the new owner. Maybe he even has a dyno sheet of the car in its current configuration.
What do you think of my thoughts and how are your own experiences of this exhaust manifold? Does anybody use it for racing or had it dyno-tested?
I'm looking forward to your feedback.
